Spectroscopy of selected copper group minerals: ktenasite, orthoserpierite and kipushite
Spectroscopy of selected copper group minerals: ktenasite, orthoserpierite and kipushite
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选定铜族矿物的光谱：钾长石、正蛇绿石和 kipushite
DOI：
10.1007/s11243-010-9378-6
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发表时间：
2010
影响因子：
1.7
通讯作者：
E. Keeffe
中科院分区：
文献类型：
--
作者：
R. Frost;B. Jagannadha Reddy;E. Keeffe
采用近红外(NIR)和红外光谱(IR)对三种复杂的铜锌硫酸盐/磷酸盐矿物(Ktenasite、斜方蛇纹石和Kipushite)进行了表征。这三种矿物的光谱特征与它们的组成和结构有很大的不同。在这些铜锌矿物的电子光谱和振动光谱中，结构阳离子取代(锌、铜)对电子能带和振动能谱都有显著影响。富锌组分和富铜组分之间不同的铜锌比对电子光谱中的铜(II)带有很大的影响。铜(II)光谱在高波数(11,390和7,545 cm−-1)处最明显。近红外和红外光谱特征反映了铜离子对锌离子的类质同象取代。Ktenasite和斜方蛇纹石中ν3和ν4(SO4)2−伸缩振动的多个谱带归因于硫酸盐离子对称性从Td降低到C2V。红柱石的红外光谱特征是在1,090和990 cm−-1处有较强的(PO4)3−振动模式。红外区的吸收范围比红柱石大，而斜方蛇纹石的红外区居中。
Near-infrared (NIR) and IR spectroscopy have been applied for the characterisation of three complex Cu–Zn sulphate/phosphate minerals, namely ktenasite, orthoserpierite and kipushite. The spectral signatures of the three minerals are quite distinct in relation to their composition and structure. The effect of structural cation substitution (Zn2+and Cu2+) on band shifts is significant both in the electronic and in the vibrational spectra of these Cu–Zn minerals. The variable Cu:Zn ratio between Zn-rich and Cu-rich compositions shows a strong effect on Cu(II) bands in the electronic spectra. The Cu(II) spectrum is most significant in kipushite (Cu-rich) with bands displayed at high wavenumbers, 11,390 and 7,545 cm−1. The isomorphic substitution of Cu2+for Zn2+is reflected in the NIR and IR spectroscopic signatures. The multiple bands for ν3and ν4(SO4)2−stretching vibrations in ktenasite and orthoserpierite are attributed to the reduction in symmetry of the sulphate ion from Tdto C2V. The IR spectrum of kipushite is characterised by strong (PO4)3−vibrational modes at 1,090 and 990 cm−1. The range of IR absorption is higher in ktenasite than in kipushite, while it is intermediate in orthoserpierite.